Starter for electrical dehydrators



F. W. HARRIS. STARTER FOR ELEcTRlcA-L DEHYDRATQRS.

APPLICATIONIILD NOV. 1,

Patented Sept.

2R9- RRZZ. y

. JIRWENTOR.

''fatented Sept.. 25, i922.

maires stares FFQ.

n malat- FORD W. HARRIS, OF LOS ANGELES, CALIFORNIA, ASSIGNOR T0PETROLEUM RECTI- i FYING COMPANY, OF SAN FRANCISCO, CALIFORNIA, AC0R1ORAION 0F CALI- ronnie.

STARTER FOR ELECTRICAL DEIEYDRATORS. I

Application lfiled November 1, l1920. Serial4 No. 420,980.

T o all whom it may comprit."

Be it known that I, FORD W. Hamusta citizen of the United States,residing in the city of Los Angeles, county'of Los Angeles, State ofCalifornia, have inventedva new and useful Improvement Comprlsing theStarters for Electrical Dehydrators,

of which the following is a specification.

My invention relates to dehydrators in which electric current is used tocause the emulsified water, carried in emulsions of oil and water, toagglomerate into'large water masses which settle' out readily by gravityor which may be separated by centrifuges or other means. I have foundthat it is possible by operating such dehydrators upon emulsions havinga low percentage of water to handle large volumes at a ,low cost but inmany cases I have found that when dehydrators, designed to be operatedin such a manner, are filled with very wet emulsions that it isdifiicult if not impossible to get them to start to operate properly dueto the inherent tendency of water rich masses to collect in the electricfield where they conduct current indefinitely greatly reducing theeffective voltage and rendering.

the apparatus inefficient if not absolutely inoperative.

I have further found that it is compara#v tively easy to dehydrateemulsions in which the water is present in the form of coarse particlesbut that where a. considerable portion of the water is in the form ofwhat may be termed ultra-microscopic particles that it is very difficultto initiate the dehydrating action due, I believe, to the fact, thatinnumerable high resistance paths form through the body of the emulsionthrough which current flows. The current flowing in any single path isof course exceedingly minute but the aggregate current flowing throughall such paths is sufficient to form a short circuit which will throwout vthe circuit breaker if the apparatus is provided with one. In theevent that the circuit is protected by reactance or resistance theeffect of this short circuit is to reduce the voltage between theelectrodes of the dehydrator to practically zero so that the dehydratingaction ceases. Many types of dehy-drators which are quite successful oncoarse emulsions cannot be started on fine emulsions due to thistendency to short circuit. I think that the4 principal ldifficulty -inthis respect is due to fine water particles and not to the percentage ofwater as I have found that the tendency toshort c1rcuitl in very wetemulsions is n o greater than the tendency to short circuit in some`emulsions in which the percentageof water is very small, in fact Il haveknown cases in whichdehydrators, which operated very well on emulsionsin which the total water \content was approximately thirty per cept,

would short circuit on oil of the same characteristics when itcontained-only one-half of one per cent of emulsion as indicated by thecentrifuge. .This percentage ofemulsion does not, however, correctlyindicate the true Water content which may have been less than one-tenthof one per cent.v

. glomeration and produce their own coarse' emulsion once they arestarted, the fine emulsion mixing therewith. andl being readily disposedof thereafter.

Previous inventors have not recognized the fact that the difficultiesmet with in the practical' operation of commercial types of dehydratorshave been due in many cases to fine emulsion nor have they recognizedthat it was very difficult if not impossible to provide properconditions for starting on fine emulsions and thereafter running on thecoarser emulsions formed in the electric field between the electrodeswithout changing the adjustment of the apparatus. Many failures ofelectrical dehydrators are due to the fact that it has been thoughtnecessary to design them so that they would operate on all sorts of oiland would be self start,

ing.

An object of my invention is to provide a dehydrator which shall beprovided with f.

Fiirther objects `and advantages will be madeevident hereinafter.

1n the drawing which is 'for illustrative purposes only,

Fig. 1 is a side elevation partly in section and Fig.f 2 is a plan, of aconvenient embodimentoi: my invention.

ln this "form of my invention, which is one of many, 11 is a tank havinga tight top and bottom and having suspended therein an electrode 12.This electrode is cylindrical and is spaced concentrically with the tank11, which is also cylindrical, the space bc tween the electrode and thetank forming the electric field 13 in which the dehydra- .tion takesplace when the apparatus is op erating normally. The electrode 12 issuspended from an insulator 14 and 'from a rod 15, which passes throughan outlet bushing 16, being connected through a suitable switch 17 withAthe secondary of a transformer 18 the other side of which is connectedto the tank 11 through a wire 19. Oil is delivered to' the tank 11through a raw oil inlet pipe 20, clean oil being with` drawn through aclean oil outlet pipe 21, and waste water being withdrawn through aywater outlet pipe 22 to a drain 23.

lf coarse emulsion is available the tank may be filled therewith throughthe pipe 20.

The electric field 13 acting on large particles agglomerates themfurther so that they fall out of the field into the bottom of the tankfrom which they may be withdrawn in the form of free water through thepipe 22, the cleaned oil being withdrawn through the pipe 21. 'ln theevent, however, that the emulsion is very fine the small water particles will build up a short circuit between the electrode 12 and thetank 11 andthe dehydrating action stops due to the loss of ingdehydrator.

' This starting dehydrator consists of a shell 30 havinga tight top inwhich is placed v an outlet bushing 31 which carries an inner electrode32J the outer end of which is connect'ed through a switch 29 to thesecondary of the transformer 18, Passing through the bottom of the shell30 is an outer electrode 33 which is in the form of a pipe whose lowerend is connected to the discharge of a centrifugal pump 34 which isdriven by any suitable motor not shown. The pump 34 takes emulsion from.below the electrode 1.2 and delivers it at a high Velocity to the spacebetween the inner electrode 32 and the outer electrode 33. The outerelectrode is flared out to pass up and around the lower end of theoutlet bushing 31:the emulsion This emulsion l preparev by means of whatmight be called a start- Y passing therethrough and being delivered fromthe shell 3Q the upper part of the tank 11 through apipe 35.

By passing the iine emulsion through the space between the inner andouter elecf trodes at a high oit speed the formation of permanent pathsthrough the ne emulsion is prevented and it is possible to maintain highvoltage between the elec trodes. The rate ot dehydration is not as rapidas in the main dehydrator hut it is possible to continuously agglomeratewater which tends to gradually bring the average size of the waterparticles in the tank 1 1 up until they are large enough to makedehydration in the iield 13 possible. llt is then possible by throwingover the switch 29 to disconnect the electrode 32. The switch 17 whichhas previously been open is then closed to connect the rod 15 to startthe maindehydrator at which time the pump 34 can be stopped. Underordinary conditions the apparatus then can be run indeii nitely bysupplying raw oil through the pipe 20 drawing oii' clean oil through theoutlet pipe 21 and water through the pipe 22.

ln some cases it is desirable to operate both the starting and the maindehydrators simultaneously the starting dehydrator being most eicient onthe liner emulsion which rises to the top of the tank 11 and the maindehydrator acting on the coarser emulsion which is at lower levels. ltis evident that this canv b e done by starting with the switch 17 openand the switch 29 closed running until coarse emulsion is built up inthe tank 11 and then closing the switch 29. The two .dehydrating actionsthen take place simultaneously and as soon as the water percentage inthe topot the tank 11 reaches the desired minimum oil can be started inthrough the pipe` 2O the apparatus thereafter functioning automatically.

1t should be noted that the main dehydrator contained in the tank 11 andthe starting dehydrator contained in the shell 30 operate upon somewhatdii'erent principles. The main dehydrator operates upon the principle ofsubjecting a practically stationary or at least a very slow moving bodyof emulsion to the action of electric current in such a manner that thecurrent paths are automatically disrupted as fast .as they form. This isonly possible when the individual paths are of suiiiciently lowresistance to allow enoughcurrent to flow to vaporize portions of that'path so that the flow of current is interrupted without the. necessityfor any mechanical means for interrupt1on. This method of operation isonly possible when the water consists in whole or in part of largedrops. The agglomeration produced by any flow of cur-- rent, of course,produces larger drops which tall out by gravity from the eld leaving thesmaller drops to form new paths which are in turn disrupted by the flowof current.

In the starting dehydrator, however, l do not depend on the action ofthe vcurrent to break up the paths but break them up me- .'chanicallydue to the rapid Vflow of liquid the field. l also do not depend onthrough settling action to remove the free water from the field, but onthe contrary l remove the water forcibly by the rapid How, theagglomerated water being delivered in 'company with the oil into themain tank ll in fornia emulsions which the water settles out from theoil in some measure so that only the finer particles are againdeliveredto the' field. When therefore the starting dehydrator has been operatingfor some time the character of the emulsion will be materially changedin' that the average size of the water particles will be veryconsiderably increased and the total amount of water will be somewhatreduced by the settlingv out of agglomeratedv water so that the maindehydrator can then be 4started operating automatically thereafterwithout the need for mechanical agitation.

l employ on the ordinary types of Cali an alternating potential of 11000volts. t' i I claim,1 as my invent-ion i 1. The process of dehydratingemulsions i which comprises circulating emulsion from a bulk supplythrough an electric field at such a-velocity that the formation of per'-manent short circuit in that field is prevented and thereaftersubjecting the coarse from said bulk supply emulsion so formedin thebulk supply tc? the action of a second electric field in which thedisruption of the current paths 'occursautomatically without mechanicalIagitation.

2. A dehydrator comprising a tank adapted to hold a bulk supply of theemulsion to be treated; .a

starting dehydrator; means for forcibly circulating emulsion dehydratorand back and means for producing an electric field in said bulk supply.

3. A dehydrator comprising a settling tank; means for drawing water 0Hfrom the bottom of said tank; a starting dehydrato-r';

'means for circulating emulsion from said settling tank through saidstarting dehydrator and back into. said settling tank and means forsubjecting the coarse emulsion produced by said circulation to theaction through said starting. to said' bulk supply; l

of an electric field located insaid settling.v

` tank.

4. A dehydrator comprising .a settling tank; electrodes in said tank; ashell; start- Foan w. nanars.'

' ing electrodes in said 4shellgpimeans for cir-

